rivt is an open source software project for writing and formatting an engineering document. The document is a text, HTML or PDF file (a rivt doc) generated from a rivt file. Each rivt file is a Python file (.py) that generates a rivt doc using rivt markup.
Groups of rivt docs can be organized and linked into rivt reports. This site is an example of a rivt report. An interface for finding public rivt files on GitHub is here.